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      1 /*
      2  * Copyright 2013 Google Inc.
      3  *
      4  * Use of this source code is governed by a BSD-style license that can be
      5  * found in the LICENSE file.
      6  */
      7 
      8 #ifndef SkFontMgr_DEFINED
      9 #define SkFontMgr_DEFINED
     10 
     11 #include "SkFontStyle.h"
     12 #include "SkRefCnt.h"
     13 #include "SkScalar.h"
     14 #include "SkTypes.h"
     15 
     16 class SkData;
     17 class SkFontData;
     18 class SkStreamAsset;
     19 class SkString;
     20 class SkTypeface;
     21 
     22 class SK_API SkFontStyleSet : public SkRefCnt {
     23 public:
     24     virtual int count() = 0;
     25     virtual void getStyle(int index, SkFontStyle*, SkString* style) = 0;
     26     virtual SkTypeface* createTypeface(int index) = 0;
     27     virtual SkTypeface* matchStyle(const SkFontStyle& pattern) = 0;
     28 
     29     static SkFontStyleSet* CreateEmpty();
     30 
     31 protected:
     32     SkTypeface* matchStyleCSS3(const SkFontStyle& pattern);
     33 
     34 private:
     35     typedef SkRefCnt INHERITED;
     36 };
     37 
     38 class SK_API SkFontMgr : public SkRefCnt {
     39 public:
     40     int countFamilies() const;
     41     void getFamilyName(int index, SkString* familyName) const;
     42     SkFontStyleSet* createStyleSet(int index) const;
     43 
     44     /**
     45      *  The caller must call unref() on the returned object.
     46      *  Never returns NULL; will return an empty set if the name is not found.
     47      *
     48      *  Passing |nullptr| as the parameter will return the default system font.
     49      *
     50      *  It is possible that this will return a style set not accessible from
     51      *  createStyleSet(int) due to hidden or auto-activated fonts.
     52      */
     53     SkFontStyleSet* matchFamily(const char familyName[]) const;
     54 
     55     /**
     56      *  Find the closest matching typeface to the specified familyName and style
     57      *  and return a ref to it. The caller must call unref() on the returned
     58      *  object. Will never return NULL, as it will return the default font if
     59      *  no matching font is found.
     60      *
     61      *  Passing |nullptr| as the parameter for |familyName| will return the
     62      *  default system font.
     63      *
     64      *  It is possible that this will return a style set not accessible from
     65      *  createStyleSet(int) or matchFamily(const char[]) due to hidden or
     66      *  auto-activated fonts.
     67      */
     68     SkTypeface* matchFamilyStyle(const char familyName[], const SkFontStyle&) const;
     69 
     70     /**
     71      *  Use the system fallback to find a typeface for the given character.
     72      *  Note that bcp47 is a combination of ISO 639, 15924, and 3166-1 codes,
     73      *  so it is fine to just pass a ISO 639 here.
     74      *
     75      *  Will return NULL if no family can be found for the character
     76      *  in the system fallback.
     77      *
     78      *  Passing |nullptr| as the parameter for |familyName| will return the
     79      *  default system font.
     80      *
     81      *  bcp47[0] is the least significant fallback, bcp47[bcp47Count-1] is the
     82      *  most significant. If no specified bcp47 codes match, any font with the
     83      *  requested character will be matched.
     84      */
     85     SkTypeface* matchFamilyStyleCharacter(const char familyName[], const SkFontStyle&,
     86                                           const char* bcp47[], int bcp47Count,
     87                                           SkUnichar character) const;
     88 
     89     SkTypeface* matchFaceStyle(const SkTypeface*, const SkFontStyle&) const;
     90 
     91     /**
     92      *  Create a typeface for the specified data and TTC index (pass 0 for none)
     93      *  or NULL if the data is not recognized. The caller must call unref() on
     94      *  the returned object if it is not null.
     95      */
     96     SkTypeface* createFromData(SkData*, int ttcIndex = 0) const;
     97 
     98     /**
     99      *  Create a typeface for the specified stream and TTC index
    100      *  (pass 0 for none) or NULL if the stream is not recognized. The caller
    101      *  must call unref() on the returned object if it is not null.
    102      */
    103     SkTypeface* createFromStream(SkStreamAsset*, int ttcIndex = 0) const;
    104 
    105     struct FontParameters {
    106         struct Axis {
    107             SkFourByteTag fTag;
    108             SkScalar fStyleValue;
    109         };
    110 
    111         FontParameters() : fCollectionIndex(0), fAxisCount(0), fAxes(nullptr) {}
    112 
    113         /** Specify the index of the desired font.
    114          *
    115          *  Font formats like ttc, dfont, cff, cid, pfr, t42, t1, and fon may actually be indexed
    116          *  collections of fonts.
    117          */
    118         FontParameters& setCollectionIndex(int collectionIndex) {
    119             fCollectionIndex = collectionIndex;
    120             return *this;
    121         }
    122 
    123         /** Specify the GX variation axis values.
    124          *
    125          *  Any axes not specified will use the default value. Specified axes not present in the
    126          *  font will be ignored.
    127          *
    128          *  @param axes not copied. This pointer must remain valid for life of FontParameters.
    129          */
    130         FontParameters& setAxes(const Axis* axes, int axisCount) {
    131             fAxisCount = axisCount;
    132             fAxes = axes;
    133             return *this;
    134         }
    135 
    136         int getCollectionIndex() const {
    137             return fCollectionIndex;
    138         }
    139         const Axis* getAxes(int* axisCount) const {
    140             *axisCount = fAxisCount;
    141             return fAxes;
    142         }
    143     private:
    144         int fCollectionIndex;
    145         int fAxisCount;
    146         const Axis* fAxes;
    147     };
    148     /* Experimental, API subject to change. */
    149     SkTypeface* createFromStream(SkStreamAsset*, const FontParameters&) const;
    150 
    151     /**
    152      *  Create a typeface from the specified font data.
    153      *  Takes ownership of the font data, so the caller should not reference it again.
    154      *  Will return NULL if the typeface could not be created.
    155      *  The caller must call unref() on the returned object if it is not null.
    156      */
    157     SkTypeface* createFromFontData(SkFontData*) const;
    158 
    159     /**
    160      *  Create a typeface for the specified fileName and TTC index
    161      *  (pass 0 for none) or NULL if the file is not found, or its contents are
    162      *  not recognized. The caller must call unref() on the returned object
    163      *  if it is not null.
    164      */
    165     SkTypeface* createFromFile(const char path[], int ttcIndex = 0) const;
    166 
    167     SkTypeface* legacyCreateTypeface(const char familyName[],
    168                                      unsigned typefaceStyleBits) const;
    169 
    170     /**
    171      *  Return a ref to the default fontmgr. The caller must call unref() on
    172      *  the returned object.
    173      */
    174     static SkFontMgr* RefDefault();
    175 
    176 protected:
    177     virtual int onCountFamilies() const = 0;
    178     virtual void onGetFamilyName(int index, SkString* familyName) const = 0;
    179     virtual SkFontStyleSet* onCreateStyleSet(int index)const  = 0;
    180 
    181     /** May return NULL if the name is not found. */
    182     virtual SkFontStyleSet* onMatchFamily(const char familyName[]) const = 0;
    183 
    184     virtual SkTypeface* onMatchFamilyStyle(const char familyName[],
    185                                            const SkFontStyle&) const = 0;
    186     virtual SkTypeface* onMatchFamilyStyleCharacter(const char familyName[], const SkFontStyle&,
    187                                                     const char* bcp47[], int bcp47Count,
    188                                                     SkUnichar character) const = 0;
    189     virtual SkTypeface* onMatchFaceStyle(const SkTypeface*,
    190                                          const SkFontStyle&) const = 0;
    191 
    192     virtual SkTypeface* onCreateFromData(SkData*, int ttcIndex) const = 0;
    193     virtual SkTypeface* onCreateFromStream(SkStreamAsset*, int ttcIndex) const = 0;
    194     // TODO: make pure virtual.
    195     virtual SkTypeface* onCreateFromStream(SkStreamAsset*, const FontParameters&) const;
    196     virtual SkTypeface* onCreateFromFontData(SkFontData*) const;
    197     virtual SkTypeface* onCreateFromFile(const char path[], int ttcIndex) const = 0;
    198 
    199     virtual SkTypeface* onLegacyCreateTypeface(const char familyName[],
    200                                                unsigned styleBits) const = 0;
    201 private:
    202     static SkFontMgr* Factory();    // implemented by porting layer
    203     friend SkFontMgr* sk_fontmgr_create_default();
    204 
    205     typedef SkRefCnt INHERITED;
    206 };
    207 
    208 #endif
    209